The invention relates to an apparatus for adjusting stator vanes of a turbo drive mechanism, in particular, especially a gas turbine.
Gas turbines include several units, such as a fan, a fuel chamber, preferably compressors as well as turbines. The component units of a gas turbine are surrounded by a fixed housing.
In a turbine as well as in a compressor of the gas turbine, fixed stator vanes are disposed, as well as rotating runner blades. The running blades are associated with at least one rotor and rotate with respect to the stator vanes and to the stationary housing. If the turbine or compressor has two or more stages, stator vanes and runner blades are arranged alternately one behind the other, while along the circumference of the rotor or housing a plurality of runner blades and stator vanes are disposed, which form so-called stator vane rings and runner blade rings.
The stationary stator vanes can be adjustable or rotatable about an axis. DE 39 13 102 C1 discloses an apparatus for the adjustment of stator vanes in which stator vanes of a single stator vane ring are connected by an adjusting lever outside of a housing of the turbo drive mechanism to an adjusting ring, while the adjusting lever or each adjusting lever engages the adjusting ring with a first end and with a second end lying opposite the first end of a shank of the particular runner blade.
Another apparatus for the adjustment of stator vanes is disclosed in DE 41 02 188 C2. DE 39 102 188 C1 shows a compressor and DE 41 02 188 C2 shows a turbine of a gas turbine engine with an apparatus for the adjustment of stator vanes.
An adjusting lever is affixed at a second end by a fastening screw to the shank of the particular stator vane. In the operation of the gas turbine it is possible due to great mechanical stresses for the fastening screw to break. In the devices known in the prior art, in the adjustment of stator vanes the problem exists that, if the fastening screw breaks, the bond between stator vane and the adjusting lever is interrupted by the adjusting blade coming entirely free of the stator vane. The stator vane can then assume any random angular position in its channel in the gas turbine. The entire gas turbine can be damaged in this manner.
Setting out from this situation the present invention is addressed to the problem of creating a novel device for the adjustment of stator vanes of a turbo engine, especially a gas turbine.
This problem is solved by a device of the present invention. According to the invention, an opening is created in the second end of the adjusting lever or every adjustable lever, and the end of the shank of the particular stator vane engages this opening. The end of the shank has a projection, and the projection protrudes over the margin of this opening when the blade is in the installed position. In case of breakage of the screw serving to affix an adjusting lever to a stator vane, the adjusting lever is prevented by the invention from completely separating from the stator vane. Accordingly it is assured by the invention that, even if this screw breaks the corresponding stator vane will maintain its angular position.
Preferably, when a particular stator vane is in the installed position, the opening associated with the second end of the adjusting lever is aligned with an opening associated with the shank of the particular stator vane such that a fastening screw passes through these openings. When the particular stator vane is in a position (wrong position) turned about 180° from the installed position, the opening associated with the second end of the adjusting lever is off-center from the opening associated with the shank. Any fastening of the adjusting lever to a stator vane in a wrong position is thereby prevented.
According to an advantageous improvement of the invention, the adjusting lever, or every adjusting lever, has an opening at the first end which, when the adjusting lever is in the installed position, is entered by a pin-like element for affixing the adjusting lever to the adjusting ring. When the particular stator vane is in the installed position, the opening associated with the first end of the stator vane is aligned with at least one opening associated with the adjusting ring, such that the pin-like element passes through these openings. When the particular stator vane is in a position (wrong position) turned about 180° away from the installed position, the opening associated with the first end of the adjusting lever is out of line with the openings associated with the stator ring. The adjusting lever is thus prevented from being fastened to a stator vane in a wrong position.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.